PURPOSE: To handily manufacture the gradient material, at the time of arranging the element to be added to an alloy on the surface of a metallic substrate, irradiating it with an energy beam and executing alloying, by controlling the output of the beam and step wise changing the chemical compsn.

CONSTITUTION: Ni, the element to be added to an alloy is arranged on the surface of a metallic substrate (Al) 3, which is irradiated with an energy beam 2 from a beam source 1 to uniformly heat the surface of the substrate 3, by which an alloy layer 4 of Al with Ni can be manufactured. At this time, the output of the electron beam is controlled to regulate the depth of penetration to successively change the Ni concn. in alloy layers 4, 5 and 6, by which the gradient compositional material can be manufactured. In this way, the gradient material in which the generation of compositional and physical discontinuity is eliminated and the generation of residual stress at the time of joining and the deterioration of mechanical strength are prevented can handily be obtd.